The present disclosure relates to a sheet feeding cassette that displaces a bottom plate loaded thereon with a sheet to a sheet feeding position by a lift-up method, a sheet feeding device thereof, and an image forming apparatus including the sheet feeding device.
In an image forming apparatus such as a copier or a printer that forms an image on a sheet by electrophotography, a sheet feeding cassette that stores a sheet is provided to be attached and detached to and from an inside of the device body. Some sheet feeding cassettes employ a lift-up method of displacing a bottom plate loaded thereon with a sheet to a sheet feeding position by rotating a lift plate that abuts on a rear face of the bottom plate. In such a sheet feeding cassette, sheets loaded on the bottom plate are picked up from an uppermost sheet, and fed to an image forming portion at a predetermined timing.
Meanwhile, since a number of sheets are loaded on the bottom plate of the sheet feeding cassette, high strength and rigidity are required for the bottom plate. Therefore, the bottom plate is generally made of metal.
Further, static electricity is generated by rubbing of sheets in feeding out a sheet from the sheet feeding cassette, and when the static electricity is accumulated in the sheet in the sheet feeding cassette, a problem of multi-feed of sheets occurs. Therefore, a grounding configuration that releases the static electricity generated by rubbing of sheets is employed.
Meanwhile, there is a problem of increase in cost when the bottom plate of the sheet feeding cassette is made of metal as in a conventional manner. Therefore, it is conceivable that the bottom plate is made of low-cost resin, however, there is a problem that the bottom plate made of resin is easily deformed.
Further, the low-strength bottom plate made of resin has a problem that a portion on which the lift plate on the rear face of the bottom plate abuttingly slides is easily worn away, and in addition, there is also a problem that non-conductive resin does not conduct static electricity, and thus grounding is difficult.
Then, it is conceivable that the bottom plate made of resin is reinforced by a reinforcing plate, however, there is a problem that such reinforcement entails increase in cost.
The present disclosure has been made in view of the above-described problems, and an object of the present disclosure is to provide a sheet feeding cassette including a bottom plate with high strength and rigidity even with low cost and a simple configuration, a sheet feeding device, and an image forming apparatus including the sheet feeding device.